README.md

DOI

dggridR: Discrete Global Grids for R

Spatial Analysis Done Right

You want to do spatial statistics, and it's going to involve binning.

Binning with a rectangular grid introduces messy distortions. At the macro-scale using a rectangular grid does things like making Greenland bigger than the United States and Antarctica the largest continent.

Mercator Projection

But this kind of distortion is present no matter what the resolution is; in fact, it shows up whenever you project a sphere onto a plane.

What you want are bins of equal size, regardless of where they are on the globe, regardless of their resolution.

dggridR solves this problem.

dggridR builds discrete global grids which partition the surface of the Earth into hexagonal, triangular, or diamond cells, all of which have the same size. (There are some minor caveats which are detailed in the vignettes.)

Discrete Global Grid in use

(Naturally, you can use much smaller cells than those shown in the image above.)

This package includes everything you need to make spatial binning great again.

Many details and examples are included in the vignette.

Installation

dggridR is available from CRAN via:

install.packages('dggridR')

If you want your code to be as up-to-date as possible, you can install it using:

library(devtools) #Use `install.packages('devtools')` if need be
install_github('r-barnes/dggridR', vignette=TRUE)

Show me some code

Okay.

Your analysis could be as easy as this:

library(dggridR)
library(dplyr)

#Construct a global grid with cells approximately 1000 miles across
dggs          <- dgconstruct(spacing=1000, metric=FALSE, resround='down')

#Load included test data set
data(dgquakes)

#Get the corresponding grid cells for each earthquake epicenter (lat-long pair)
dgquakes$cell <- dgtransform(dggs,dgquakes$lat,dgquakes$lon)

#Get the number of earthquakes in each equally-sized cell
quakecounts   <- dgquakes %>% group_by(cell) %>% summarise(count=n())

Show me more examples!

In R, typing

vignette('dggridR')

will bring up many examples.

But I want higher resolution grids than that

Many different grid resolutions are available for many different grids. The following chart shows the number of cells, their area, and statistics regarding the spacing of their center nodes for the ISEA3H grid type.

|Res |Number of Cells | Cell Area (km^2) | Min | Max | Mean | Std | |---:|----------------:|-----------------:|------------:|------------:|------------:|----------:| | 1 | 32 | 17,002,187.39080 | 4,156.18000 | 4,649.10000 | 4,320.49000 | 233.01400 | | 2 | 92 | 5,667,395.79693 | 2,324.81000 | 2,692.72000 | 2,539.69000 | 139.33400 | | 3 | 272 | 1,889,131.93231 | 1,363.56000 | 1,652.27000 | 1,480.02000 | 89.39030 | | 4 | 812 | 629,710.64410 | 756.96100 | 914.27200 | 855.41900 | 52.14810 | | 5 | 2,432 | 209,903.54803 | 453.74800 | 559.23900 | 494.95900 | 29.81910 | | 6 | 7,292 | 69,967.84934 | 248.80400 | 310.69300 | 285.65200 | 17.84470 | | 7 | 21,872 | 23,322.61645 | 151.22100 | 187.55000 | 165.05800 | 9.98178 | | 8 | 65,612 | 7,774.20548 | 82.31100 | 104.47000 | 95.26360 | 6.00035 | | 9 | 196,832 | 2,591.40183 | 50.40600 | 63.00970 | 55.02260 | 3.33072 | | 10 | 590,492 | 863.80061 | 27.33230 | 35.01970 | 31.75960 | 2.00618 | | 11 | 1,771,472 | 287.93354 | 16.80190 | 21.09020 | 18.34100 | 1.11045 | | 12 | 5,314,412 | 95.97785 | 9.09368 | 11.70610 | 10.58710 | 0.66942 | | 13 | 15,943,232 | 31.99262 | 5.60065 | 7.04462 | 6.11367 | 0.37016 | | 14 | 47,829,692 | 10.66421 | 3.02847 | 3.90742 | 3.52911 | 0.22322 | | 15 | 143,489,072 | 3.55473 | 1.86688 | 2.35058 | 2.03789 | 0.12339 | | 16 | 430,467,212 | 1.18491 | 1.00904 | 1.30335 | 1.17638 | 0.07442 | | 17 | 1,291,401,632 | 0.39497 | 0.62229 | 0.78391 | 0.67930 | 0.04113 | | 18 | 3,874,204,892 | 0.13166 | 0.33628 | 0.43459 | 0.39213 | 0.02481 | | 19 | 11,622,614,672 | 0.04389 | 0.20743 | 0.26137 | 0.22643 | 0.01371 | | 20 | 34,867,844,012 | 0.01463 | 0.11208 | 0.14489 | 0.13071 | 0.00827 |

Credits

The code in the 'src' directory is based off of DGGRIDv6.2b by Kevin Sahr.

However, Richard Barnes has made some significant alterations. These include:

The package relies on several libraries, as noted in the Licensing section below.

Licensing

This package uses the following libraries:

This package, and all code and documentation not otherwise mentioned above (essentially anything outside the src/ directory of this package) are released under the MIT (Expat) license, as stated in the LICENSE file. The LICENCE file exists for use with CRAN.

Disclaimer

This package should operate in the manner described here, in the package's main documentation, and in Kevin Sahr's dggrid documentation. Unfortunately, none of us are paid enough to make absolutely, doggone certain that that's the case. That said, if you find bugs or are seeking enhancements, we want to hear about them.

Citing this Package

Please cite this package as:

Richard Barnes (2017). dggridR: Discrete Global Grids for R. R package version 2.0.4. "https://github.com/r-barnes/dggridR/" doi:10.5281/zenodo.1322866



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dggridR documentation built on April 30, 2020, 1:05 a.m.